In the syntheses of silicone-modified olefin waxes, use of various polyethylene oligomers, such as polyethylene oxide wax, acid anhydride-modified polyethylene wax and polyethylene oligomer having a carboxyl group at one terminal, has been heretofore studied.
In case of use of the polyethylene oxide wax, however, there is a disadvantage that a homogeneous silicone-modified polyethylene wax cannot be obtained even if the polyethylene oxide wax is modified with silicone, because the number of carboxyl groups in one molecule of the wax is 1 or less. In case of use of the acid anhydride-modified polyethylene wax, the wax is allowed to react with a double bond-containing epoxy compound, followed by addition-reaction with hydrogen silicone in the presence of a catalyst. In this case, however, since a polyethylene wax containing plural double bonds is used as an addition-reaction raw material in the addition reaction, there is a disadvantage that unless expensive hydrogen silicone having only one SiH bond in one molecule is used as hydrogen silicone to be reacted with the polyethylene wax, the silicone wax obtained after the reaction is crosslinked to gel. In case of use of the polyethylene oligomer having a carboxyl group at one terminal, there is a disadvantage that a silicone-modified polyethylene wax of high purity cannot be obtained because the polyethylene oligomer usually has a low purity of about 80%, and there is a disadvantage that a high-purity polyethylene oligomer having a carboxyl group at one terminal has a low molecular weight of about 400, so that if such a polyethylene oligomer is used, performance of a wax is not sufficiently exhibited.
Then, development of olefin waxes employable for syntheses of silicone-modified olefin waxes and high-purity silicone-modified polyethylene waxes using the olefin waxes and containing no free silicone has been desired.
Conventionally, cosmetics containing liquid oils, such as paraffin, ester, higher alcohol and glyceride, for the purpose of imparting softness, smoothness and emollient effect, have been employed. However, such conventional cosmetics cannot avoid oiliness, tackiness and oil film feeling, so that cosmetics to which silicone oils such as dimethylpolysiloxane have been blended in order to inhibit oiliness, tackiness and oil film feeling are also known.
The silicone oils have light spread, and superior smoothness and water repellency, but on the other hand, there are disadvantages that they have poor compatibility with hydrocarbon-based liquid oils, and because of low surface tension, they diffuse rapidly and have poor durability. On this account, an attempt to solidify silicone oils has been made. As materials to solidify silicone oils, a compound wherein an alkyl group is introduced into the silicone chain (Japanese Patent Laid-Open Publication No. 2-64115/1990), a compound wherein an ester group of an aliphatic alcohol or acid of 21 to 30 carbon atoms is introduced into the silicone chain (Japanese Patent Laid-Open Publication No. 10-500431/1998), acrylate silicone (Japanese Patent Laid-Open Publication No. 2-132141/1990), etc. have been proposed. In case of the compound wherein an alkyl group or a long-chain aliphatic ester group is introduced into the silicone chain, however, it is difficult to smoothly solidify the silicone oil itself, and it is general to allow a liquid oil agent, such as ester oil, triglyceride oil or paraffinic oil, to coexist in order to improve affinity of the silicone oil for waxes and thereby solidify the silicone oil. In case of the acrylate silicone, the silicone oil forms a solid even if it is used alone, but the solid is resinous and lacks smoothness required for cosmetics. That is to say, in the existing circumstances, any solid sufficiently exhibiting properties of silicone oils and having satisfactory smoothness has not been obtained yet.